A conventional rotary switch is generally constructed as a device that has a rotating shaft connected to one terminal capable of making or breaking a connection to one or more other terminals. During operation, a user manipulates the switch to manually select a circuit.
Rotary switches are often mounted upon panels and other supporting structures in order that a user may control an electrical device. It is common for a portion of the switch to be on one side of the panel (the user side) and another portion of the switch to be on the other side of the panel (the inside). In many instances, the only portion of a switch that is on the user's side of the panel is a section of the shaft and a knob or other actuating means. Generally, the bulk of the switch is on the inside of the panel. For many years this type of configuration was sufficient, but over time the size of electrical devices became increasingly smaller and there became a need to reduce the size of the switch—especially that portion on the inside of the panel and the overall height of the switch.
In order to meet the needs of smaller devices having less room and of a lower profile, the size of the components of the switches also became smaller. Yet, because these switches are comprised in part of mechanical components, there remained a practical limit as to how small they could become while still remaining useful. There became a need for different designs rather than just a reduction in the size of the components. One such attempt at providing a solution is found in U.S. Pat. No. 7,109,430 B2 issued to Horton et al. While the switch described by Horton may have resulted in a lower overall profile of the combined components, this switch still does not address at least several problems. For instance, the rotary switch 100 is constructed such that the axis of rotation of the rotary shaft 130 can only be installed perpendicularly to the printed wiring board 150 (PWB). Further, the rotary shaft 130 occupies the centre of the rotary switch 100, thereby blocking the placement of a centre push style switch in that location. Also, the rotary switch 100 assembly is complicated in design, and requires the performance of costly and error prone manufacturing techniques. Moreover, the rotary switch 100 requires the construction and installation of an electrical contact 140 that has electrical contacts which sweep across the PWB 150 selectively making and breaking electrical connections. These connections are prone to increased rates of failure since they are subject to wear and contamination by dirt, etc.
Accordingly, the industry sought to improve upon the rotary switch disclosed in Horton. One such improvement to the switch disclosed in Horton has been to use a rotary switch having an annular shaped dial which may be rotated about a centre knob. The dial includes a plastic ring having a precision inset moulding used to selectively make and break electrical connections when the dial is rotated. A small and precision metal stamping activation spring is needed for connecting purposes. Although providing a lower profile than the Horton switch, these types of improved rotary switches are complicated and require special control injection manufacturing techniques to manufacture, and thus are costly to manufacture. Also, they are designed to be mounted only in one orientation, i.e. parallel to the PWB such that the axis of rotation of the dial is perpendicular to the PWB.
Accordingly, there exists a need for an improved rotary switch which has one or more of the following characteristics: a low profile, inexpensive to manufacture, reliable, less prone to failure, less complicated, does not require precision manufacturing techniques and components, which permits the use of a centre mounted switch assembly, and that is more versatile in the orientations in which it can be mounted relative to a PWB.